SOLUTION: sin(Arccos(-2/5) I need help finding the wrapping function of (-2/5) I am not quite sure on how to find the denominator of 5. Our teacher only taught us 2,3,4,6,8, and 12. Thank

Algebra ->  Trigonometry-basics -> SOLUTION: sin(Arccos(-2/5) I need help finding the wrapping function of (-2/5) I am not quite sure on how to find the denominator of 5. Our teacher only taught us 2,3,4,6,8, and 12. Thank      Log On


   



Question 448516: sin(Arccos(-2/5)
I need help finding the wrapping function of (-2/5) I am not quite sure on how to find the denominator of 5. Our teacher only taught us 2,3,4,6,8, and 12. Thank you for your help!

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
sin(Arccos(-2/5))
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The point is on a circle of radius 5, and the x value is -2
It's the 2nd quadrant (the principal value).
Find the y value.
y%5E2+=+5%5E2+-+2%5E2+=+21
y = sqrt(21)
sine+=+sqrt%2821%29%2F5